This invention relates to air and water supplying devices for endoscopes, and more particularly to an air and water supplying device capable of discharge the water left in a water supplying path connected between a cleaning water storing tank and an endoscope and in a water supplying tube within the endoscope.
An endoscope, especially an endoscope for examining the digestive organs, is used to observe a portion of the body cavity through the window at the top end part of a flexible elongated pipe of the endoscope inserted into the body cavity. It is necessary to suitably inflate the portion to be examined by supplying air in order to provide an observing distance between the body portion to be examined and the top end part of the endoscope. Furthermore, a supply of water must be provided at the portion to be examined in order to clean the lens in the window provided at the top end part of the endoscope, or to remove dirt from the window, or to clean the portion to be observed.
For this purpose, the endoscope of this type is provided with an air and water supplying mechanism in which an air supplying tube and a water supplying tube connected to the manual operating section of the endoscope are connected through a supply air and water switching valve mechanism to an air and water supplying tube. The supply tube extends through the flexible pipe of the endoscope to the top end part so that air or water can be suitably supplied to the portion to be examined while the endoscope is being operated.
If the use of such a conventional endoscope is suspended immediately after water has been supplied thereto, the cleaning water is left in the water supplying path of the water supplying system thereof after the examination. It is very difficult to remove the water left in the water supplying tube which extends from the water storing tank to the endoscope. The end portion of the air and water supplying tube opened at the top end of the endoscope is contaminated by the water which is caused to flow backwardly into the tube by the internal pressure of the body. Furthermore, the water left in the water supplying system is liable to be spoiled. Accordingly, it is not sanitary to use the endoscope again with any water remaining in the water supplying system. The water supplying system is made up of plastic tubes. Because of the water absorbing characteristic of the plastic tube and the corrosion of the connections of the water supplying system, water may also leak out of the water supplying system.
In order to observe a portion of the body cavity to be examined with an endoscope, it is necessary to inflate the portion to be examined to a certain extent. For this purpose, the air pump is provided for the endoscope. The air supplying pressure of the air pump is relatively high, because it is utilized also for supplying water to clean the observing window of the endoscope.
With a conventional air supplying means, the period of time during which air is supplied into the body cavity by the air pump is controlled to adjust the quantity of air supplied into the body cavity. However, in such an air supplying quantity controlling method, air is supplied under a pressure much higher than the pressure which a portion of the body cavity to be examined can withstand. Therefore, the excessively high pressure may cause extreme discomfort to a patient and may rupture the body cavity.
Depending on portions of the body cavities to be examined such as the stomach, the esophagus and the duodenum, the necessary quantity of air to be supplied thereinto is different. However, in conventional methods, the same quantity of air is supplied thereinto. As a result, the observing conditions of these portions having different conditions of walls thereof are varied, and the images formed by the endoscope are therefore varied, which may result in errors in the diagnoses.
In the diagnosis by observing a portion to be examined with an endoscope for a correct diagnosis it is essential to variously change the condition of expansion of the portion to dynamically observe it. However, with air supplying means of the conventional device, it is very difficult to control the air supplying quantity for dynamically observing the conditions of expansion of the portion to be examined.
The operation of an endoscope is carried out by delivery of cleaning water to a portion of the body cavity to be examined to remove mucus, etc. from the observing window of the endoscope or to clean the portion to be examined so that the portion to be examined can be sufficiently observed. The cleaning water used in this operation and the mucus in the body cavity should be forcibly discharged out of the body by using a suction mechanism.
For this purpose, heretofore, the suctions mechanism of this type comprises a suction pump which is operated by a power device and is connected to a suction pipe opened in the top end part of the endoscope. The suction operation of the suction mechanism is carried out intermittently during observation. Since the suction pump cannot start instantaneously, the power device is maintained in operation during the observation so that the suction pump operates instantaneously to meet the requirement of suction. During the ordinary operating time, the suction pressure of the suction pump is reduced or eliminated by suction air from an air passing pipe which is opened in the finger placing surface of a piston protruding from the manual operating section body of the endoscope. When suction is required, the finger is placed on the finger placing surface of the piston to depress the latter. In this operation, the air passing pipe opened in the finger placing surface is closed by the finger, and therefore the suction pressure of the suction pump is increased. As a result, the cleaning water or the like is discharged through the sucking pipe.
The conventional device as described above is advantageous in that the suction is effected instantaneously merely by placing the finger on the top of the piston. However, it is still disadvantageous for the following reasons. If, during the operation of the endoscope, the operator is enthusiastic for the observation or the operation of the endoscope, he may inadvertently place his finger on the top of the piston to close the air passing pipe to unnecessarily suck out matter in the body cavity. Furthermore, in order to avoid this unnecessary suction, he has to keep his finger off the top of the piston intentionally, which leads to fatigue.
As mentioned, in observing for instance a portion of the stomach with an endoscope, it is necessary to send air thereinto to provide an observing distance between the endoscope and the portion to be examined, or to inflate the body cavity. With an endoscope provided with the above-described prior art air supplying device and suction device, the conditions of a portion to be examined can be dynamically observed during the process in which, after air is supplied into the body cavity by the air supplying device to excessively expand the portion to be examined and the air is gradually removed from the body cavity by the suction device. The conventional suction device is operated by closing the end of the air passing pipe with the finger, but it is difficult to suitably adjust the degree of suction with the sensual operation of the finger. Thus, the conventional device is not practical.